CN107202152B - A double transmission ratio less tooth difference-harmonic gear reducer - Google Patents

Abstract

The invention discloses a double transmission ratio small tooth difference-harmonic gear reducer, comprising a small tooth difference planetary transmission mechanism, a harmonic gear transmission mechanism and an internal gear. When the input shaft rotates, the planetary outer gear is meshed with the inner gear, but the planetary outer gear is also restricted by the input shaft and moves in a plane. shaft, realize the first-stage deceleration, and obtain a set of transmission ratios; at the same time, the wave generator makes the flexible wheel produce controllable elastic deformation and meshes with the rigid wheel, realizes the second-stage deceleration, and obtains another set of transmission ratios. The invention can output multiple transmission ratios, has a large transmission ratio range, and can output the dual transmission ratios in opposite directions of the coaxial line.

Description

A double transmission ratio less tooth difference-harmonic gear reducer

technical field

The invention belongs to the field of mechanical transmission, in particular to a double transmission ratio less tooth difference-harmonic gear reducer.

Background technique

Harmonic gear transmission technology was invented by American scientist C.W.Musser in 1955. The transmission is a new type of transmission that relies on elastic deformation motion to achieve the purpose of transmission. Because it changes the traditional transmission principle, it has the advantages of simple structure, light weight, large transmission ratio range, high transmission precision, large bearing capacity, small backlash, even no backlash transmission, large number of meshing teeth at the same time and can achieve Confined space transmits motion and power and many other advantages. Harmonic gear drives are widely used in the fields of automatic control, mechatronics, numerical control equipment, aerospace and robotics.

Small tooth difference planetary gear transmission is a planetary gear mechanism composed of N type or NN type when the difference in the number of teeth between the inner gear and the outer gear is small. The characteristics of this kind of transmission are large transmission ratio, small volume, light weight, stable operation, easy processing of tooth profile, and convenient disassembly and assembly. Reasonable design, manufacture and lubrication can achieve higher transmission efficiency. Compared with the ordinary planetary gear transmission, the planetary transmission structure with less tooth difference is simpler and the assembly is relatively simple.

However, the lower limit of the transmission ratio of the harmonic gear transmission is relatively large, and the transmission ratio can generally not be less than 35. When the harmonic multi-stage transmission is used, the deformation of the flexible wheel is increased, the force is more complex, the stiffness is reduced, and the overall processing and assembly are more difficult. The single-stage transmission ratio of the planetary gear transmission with small tooth difference is smaller than that of the harmonic transmission. In order to increase the transmission ratio, when the planetary gear transmission is used alone, it is necessary to increase the volume of the reducer, increase the weight, and the structure is complicated, and the application range is reduced.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a double transmission ratio less tooth difference-harmonic gear reducer, which solves the problem that the lower limit value of the transmission ratio of the harmonic gear transmission is large, the deformation of the flexible wheel of the harmonic multi-stage transmission is increased, the force is complex, and the rigidity is The problems of descending, difficult processing and assembly, and the problems of large volume and weight, complex structure and difficult assembly of multi-stage planetary gear transmission to obtain a large transmission ratio.

The technical solution to achieve the purpose of the present invention is: a double transmission ratio small tooth difference-harmonic gear reducer, including a small tooth difference planetary transmission mechanism, a harmonic gear transmission mechanism and an internal gear, and the small tooth difference planetary transmission mechanism as the first gear. The first-stage deceleration mechanism, the harmonic gear transmission mechanism is used as the second-stage deceleration mechanism, and the small tooth difference planetary transmission mechanism and the harmonic gear transmission mechanism are connected by internal gears.

The inner gear is annular, and the two end faces are respectively provided with ring gears. The ring gear on one end face is a rigid gear ring gear driven by a harmonic gear and meshes with the harmonic gear transmission mechanism, and the other gear ring is a planet with a small tooth difference. The inner gear ring gear of the transmission meshes with the planetary transmission mechanism with small tooth difference.

The small tooth difference planetary transmission mechanism adopts an involute small tooth difference planetary gear train, the transmission form is N type, and the input shaft is an eccentric shaft.

The inner gear and the outer gear of the planetary transmission mechanism with small tooth difference adopt two-tooth difference, and the modulus is 1.

The planetary transmission mechanism with small tooth difference adopts a pin shaft type output mechanism, and each pin shaft is sleeved with a load-equalizing and wear-reducing shaft sleeve.

The harmonic gear transmission mechanism includes an output end cover, a crossed roller bearing, a flexible wheel, a wave generator shaft, a flexible bearing and an end cover. The flexible wheel adopts a hat-shaped flexible wheel, and the center of the output end cover is provided with a through hole. The inner wall of the cover is provided with a bearing seat, the wave generator shaft adopts a five-stage shaft section, the first shaft section is a cam section, and its end face is used to connect with the pin disk of the planetary transmission mechanism with small tooth difference, the second shaft section, the third shaft section , The fourth shaft section and the fifth shaft section are stepped shafts with decreasing cross-sectional areas. One end of the fifth shaft section protrudes from the through hole in the center of the output end cover and the center hole of the end cover. The third shaft section and the fourth shaft section They are respectively matched with bearings. The bearings are arranged in the bearing seat in the output end cover and play a supporting and limiting role. The end cover cooperates with the output end cover to limit the axial movement of the bearing; the cam section of the wave generator shaft is connected to the flexible The inner ring of the bearing is matched, the end face of the outer ring of the flexible bearing is matched with the bottom end face of the flexible wheel, the inner gear is fixed with the inner ring of the crossed roller bearing and cannot be fixed; The three wheels are fixedly connected, and the three move together with the flexible wheel; after the planetary transmission mechanism with small tooth difference decelerates, the pin-shaft output mechanism transmits the motion to the wave generator shaft, and the rotation of the wave generator shaft causes the flexible wheel to generate periodic The deformation further makes the flexible wheel mesh with the teeth on the other end of the internal gear to realize the second-stage deceleration.

The flexible gear of the harmonic gear transmission mechanism adopts an involute spur gear.

The internal gear adopts an involute spur gear.

Compared with the prior art, the present invention has significant advantages as follows: (1) It has high and low transmission ratio outputs, and the transmission ratio range is large, the minimum transmission ratio is 7, the maximum can reach tens of thousands, and the two transmission ratios can be the same The output is in the opposite direction of the axis; (2) The whole machine has a compact structure, a small number of parts, and a small volume of the whole machine, and the application range is wider.

Description of drawings

FIG. 1 is a schematic diagram of the overall structure of the dual transmission ratio less tooth difference-harmonic gear reducer according to the present invention.

FIG. 2 is a schematic diagram of the cooperation relationship between the output mechanism and the planetary external gear of the dual transmission ratio less tooth difference-harmonic gear reducer of the present invention.

FIG. 3 is a schematic diagram of the assembly of the wave generator shaft and the output mechanism of the dual transmission ratio less tooth difference-harmonic gear reducer according to the present invention.

FIG. 4 is a schematic diagram of motion of the planetary transmission mechanism with small tooth difference of the double transmission ratio small tooth difference-harmonic gear reducer of the present invention.

FIG. 5 is a schematic diagram of the motion of the harmonic gear transmission mechanism of the dual transmission ratio less tooth difference-harmonic gear reducer of the present invention.

Detailed ways

The present invention will be described in further detail below with reference to the accompanying drawings.

1 to 5, a dual transmission ratio small tooth difference-harmonic gear reducer according to the present invention includes a small tooth difference planetary transmission mechanism, a harmonic gear transmission mechanism and an internal gear 4, and a small tooth difference planetary transmission. The mechanism is used as the first-stage deceleration mechanism, the harmonic gear transmission mechanism is used as the second-stage deceleration mechanism, and the small-tooth difference planetary transmission mechanism and the harmonic gear transmission mechanism are connected through the internal gear 4 . There is a groove in the center of the input end of the wave generator shaft 5 of the harmonic gear transmission mechanism, and one end of the eccentric shaft 7 of the planetary transmission mechanism with small tooth difference is matched with the groove in the center of the input end of the wave generator shaft 5 through a bearing, so One end of the eccentric shaft 7 is the end sleeved with the pin disc 12 , and the input end face of the wave generator shaft 5 is fixedly connected to the pin disc 12 by bolts.

Small tooth difference planetary transmission mechanism adopts involute small tooth difference planetary gear train, K-H-V (N type) transmission form, including bearing seat 6, eccentric shaft 7, end cover 8, planetary outer gear 9 and output mechanism. The output mechanism includes a pin shaft 10, a shaft sleeve 11 and a pin disc 12. In order to reduce the friction between the pin shaft 10 and the planetary external gear 9, and to make the force on the pin shaft 10 more uniform, a The bushing 11 is added. As shown in FIG. 2 , the evenly distributed pin shafts 10 and the shaft sleeves 11 on the pin plate 12 are screwed into the corresponding evenly distributed holes on the planetary outer gear 9 . The eccentric shaft 7 is the input shaft and also has the function of supporting the output mechanism. The inner gear 4 is fixed, the planetary outer gear 9 and the eccentric shaft section of the eccentric shaft 7 cooperate with each other through bearings, and the planetary outer gear 9 is located in the inner gear 4 . The end cover 8 at the input end is located on the end face of the bearing seat 6 , the stepped shaft section of the eccentric shaft 7 passes through the support seat 6 and the end cover 8 , and a bearing is provided between the eccentric shaft 7 and the bearing seat 6 , which is limited by the end cover 8 .

When the eccentric shaft 7 receives power and rotates, it drives the planetary outer gear 9 to move, so that the planetary outer gear 9 meshes with the ring gear at one end of the inner gear 4, so that the outer gear 9 moves in a plane, that is, the outer gear 9 not only revolves around the axis of the inner gear 4 It performs circular translational motion and rotary motion around its own axis. The rotary motion rotating around its own axis is converted into rotary motion rotating around the fixed axis through the output mechanism, and the motion output by the wave generator shaft 5 at this time is the motion decelerated by the first set of transmission ratios. Its motion diagram is shown in Figure 4.

The calculation formula of the transmission ratio i ₁ obtained by the first stage deceleration is:

In the formula, z ₉ is the number of teeth of the outer planetary gear 9, and z ₄₁ is the number of teeth of the ring gear where the inner gear 4 meshes with the outer planetary gear 9.

The diameter of the center circle where the pin shaft 10 on the pin plate 12 is located and the diameter of the center circle of the corresponding uniform holes on the planetary outer gear 9 are both Dw, the diameter d of the uniform holes on the planetary outer gear 9 and the outer diameter dw of the shaft sleeve 11 Should satisfy the following formula:

where e is the eccentric distance of the eccentric shaft 7 .

The pin plate 12 and the wave generator shaft 5 are fixedly connected together by screws, and the connection form is shown in FIG. 3 .

The harmonic gear transmission mechanism includes an output end cover 1, a crossed roller bearing 2, a flexible wheel 3, a wave generator shaft 5, a flexible bearing 13 and an end cover 14. The flexible wheel 3 adopts a hat-shaped flexible wheel, and the output end cover 1 There is a through hole in the center, a bearing seat is arranged on the inner wall of the output end cover 1, the wave generator shaft 5 adopts a five-stage shaft section, the first shaft section is a cam section, and its end face is used for the pin plate 12 of the planetary transmission mechanism with small tooth difference. The second shaft section, the third shaft section, the fourth shaft section and the fifth shaft section are stepped shafts with decreasing cross-sectional areas, and one end of the fifth shaft section extends from the through hole in the center of the output end cover 1 and the center of the end cover 14 The hole protrudes, and the third shaft segment and the fourth shaft segment are respectively matched with the bearing, which is arranged in the bearing seat in the output end cover 1 and plays a supporting and limiting role. The end cover 14 cooperates with the output end cover 1 to limit the axial movement of the bearing.

The wave generator adopts a camshaft type wave generator. The cam section of the wave generator shaft 5 is matched with the inner ring of the flexible bearing 13 , and the end face of the outer ring of the flexible bearing 13 is matched with the bottom end face of the flexible wheel 3 . The inner gear 4 is fixedly connected with the inner ring of the crossed roller bearing 2 and is fixed. The outer ring of the crossed roller bearing 2 , the end cover 1 and the flexible wheel 3 are fixedly connected, and the three move together with the flexible wheel 3 . After the planetary transmission mechanism with small tooth difference decelerates, the pin-shaft output mechanism is used to transmit the motion to the wave generator shaft 5. The rotation of the wave generator shaft 5 causes the flex wheel 3 to produce periodic deformation, which further makes the flex wheel 3 and the internal gear 4 separate. The teeth at one end mesh with each other to achieve the second stage of deceleration. Its motion diagram is shown in Figure 5.

The calculation formula of the transmission ratio i ₂ obtained by the second stage deceleration is:

In the formula, z ₃ is the number of teeth of the flex wheel 3, and z ₄₂ is the number of teeth of the ring gear where the internal gear 4 meshes with the flex wheel.

The inner gear 4 , the planetary outer gear 9 of the planetary gear train with small tooth difference and the flexible gear 3 of the harmonic gear mechanism all use involute spur gears.

The inner gear 4 is annular, and the two end faces are respectively provided with ring gears. The ring gear on one end face is a rigid gear ring gear driven by a harmonic gear and meshes with the flexible gear 3, and the ring gear on the other end is a planetary transmission with a small tooth difference. The inner gear ring gear meshes with the planetary outer gear 9. The inner gear 4 is equivalent to integrating the rigid wheel of the harmonic gear transmission mechanism with the inner gear of the planetary transmission mechanism with small tooth difference, and the end face of the ring gear meshing with the planetary outer gear 9 is provided with a flange and a groove. , the flange is used to be fixed with the frame, and the groove is matched with the bearing seat 6. The other end face of the internal gear 4 is also provided with a flange to cooperate with the inner ring of the crossed roller bearing 2 . The above-mentioned cooperation between the internal gear 4 and the bearing seat 6 and the inner ring of the crossed roller bearing 2 is fixed by screw connection.

The first group of transmission ratios obtained by the double transmission ratio less tooth difference-harmonic gear reducer according to the present invention can connect the wave generator shaft 5 with the working machine through the coupling to output movement; the second group of transmission ratios can be output through the output The flange connects the end cover 1 with the working machine to output movement.

The single-stage transmission ratio of the planetary transmission mechanism with small tooth difference is about 7-100, and the single-stage transmission ratio of the harmonic gear transmission mechanism can reach 300. Therefore, the double transmission ratio of the present invention is less tooth difference-harmonic gear reducer. The first group of gear ratios ranges from about 7-100, and the second group of gear ratios can reach thousands, even tens of thousands.

The invention makes full use of the advantages of the harmonic gear transmission mechanism and the planetary transmission mechanism with small tooth difference, and has a large variable range of transmission ratio, and the two transmission ratios can be output on a coaxial line. The volume is excessively increased, the gear is easy to process, the structure is simple, and the disassembly and assembly are convenient. The invention effectively avoids the disadvantages of a large lower limit value of the transmission ratio of the harmonic gear transmission and difficult processing and assembly of the multi-stage transmission, and the defects of a large volume and a complex structure of the multi-stage transmission of the planetary transmission with small tooth difference.

Claims (6)

1. a kind of double transmission ratio few teeth difference-harmonic gear reducers, it is characterised in that: including little gear difference planetary driving mechanism, humorous Wave gear drive and internal gear (4), little gear difference planetary driving mechanism is as first order deceleration mechanism, harmonic gear transmission machine Structure is connected as second level deceleration mechanism, little gear difference planetary driving mechanism and harmonic gear drive mechanism by internal gear (4)；

The internal gear (4) is annular, and gear ring is respectively equipped on two end faces, and the gear ring of one of end face is harmonic gear biography Dynamic firm gear gear ring is engaged with harmonic gear drive mechanism, another gear ring is the internal gear gear ring of small Tooth Number Difference Planetary Transmission and lacks Gear difference planetary driving mechanism engagement；

The harmonic gear drive mechanism includes output end cap (1), crossed roller bearing (2), flexbile gear (3), wave producer axis (5), flexible bearing (13) and end cap (14), flexbile gear (3) use carnival hat shape flexbile gear, and output end cap (1) center is equipped with through-hole, output End cap (1) inner wall be equipped with bearing block, wave producer axis (5) use five rank shaft parts, the first shaft part be cam segment, end face be used for The pin disk (12) of little gear difference planetary driving mechanism connects, and the second shaft part, third shaft part, the 4th shaft part and the 5th shaft part are section face The multi-diameter shaft that product is sequentially reduced, the 5th shaft part one end are stretched out from the through-hole and end cap (14) centre bore for exporting end cap (1) center, the Respectively with bearing fit, the bearing, which is arranged, to be exported in the bearing block in end cap (1) for three shaft parts, the 4th shaft part, plays support Position-limiting action, end cap (14) and output end cap (1) cooperation, limit the axial movement of bearing；The cam segment of wave producer axis (5) with The inner ring of flexible bearing (13) cooperates, and the end face of the outer ring of flexible bearing (13) and the bottom end face of flexbile gear (3) cooperate, internal gear (4) it is connected with the inner ring of crossed roller bearing (2), it is fixed；Outer ring, end cap (1) and the flexbile gear of crossed roller bearing (2) (3) three is connected, and three is together as flexbile gear (3) move；Little gear difference planetary driving mechanism uses pin type output mechanism after slowing down It transmits motion to wave producer axis (5), wave producer axis (5) rotates so that flexbile gear (3) generates periodically deformation, further So that flexbile gear (3) is meshed with the tooth of internal gear (4) other end, realize that the second level is slowed down.

2. double transmission ratio few teeth difference-harmonic gear reducers according to claim 1, it is characterised in that: the few teeth difference Epicyclic transmission mechanism uses involute planetary gear train, and driving form is N-type, and input shaft is eccentric shaft.

3. double transmission ratio few teeth difference-harmonic gear reducers according to claim 1, it is characterised in that: the few teeth difference The internal gear and external gear of epicyclic transmission mechanism use two teeth difference, and modulus is 1.

4. double transmission ratio few teeth difference-harmonic gear reducers according to claim 1, it is characterised in that: the few teeth difference Epicyclic transmission mechanism uses pin type output mechanism, and load anti-attrition axle sleeve is cased on every pin shaft.

5. double transmission ratio few teeth difference-harmonic gear reducers according to claim 1, it is characterised in that: the harmonic wave tooth The flexbile gear (3) of wheel drive mechanism uses involute spur gear.

6. double transmission ratio few teeth difference-harmonic gear reducers according to claim 1, it is characterised in that: the internal gear (4) involute spur gear is used.